Question:
Why are printers reluctant to sign off on a proof for one of my jobs?

Answer:
There are major risks to the printer. You best understand the objectives and nuances of your job. The printer undertakes substantial liability if it honors your verbal instructions to proof work for you. Even if your instructions are in writing, printers feel that, if something goes wrong, they can win a legal dispute but still run the risk of losing you, the customer. There are few absolutes in the buying and selling of print, but customer sign off on a proof is one of them.